Improvement in screw-cutting dies



lllivlTrrD STATES PATENT OFFICE.

JOHN J. GRANT, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE PRATT & WHITNEY COMPANY, OF SAME PLACE; I

IMPROVEMENT IN SCREW-CUTTING DIES.

Specification forming part of Letters Patent No. 173.780, dated February 22, 1876 application filed` December 2, 1875. I

Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Screw-Cutting Dies 5 andl do hereby declare that the following is a full, clear, and exact description thereof, whereby a person skilled in the art can make and use the same, reference being had to the accompanying drawing, and to the letters of' reference marked thereon.

Like letters in the figures indicate the same parts.

My invention relates to dies, such as are used in suitable 'die-stocks or machines, for the purpose of cutting screw-lhreads upon metallic bars.

The object of my invention is to provide an adjustable die, which can be varied to suit a small difference ot diameter in the screw, or to allow for the wear occasioned by use.

In the accompanying drawing, Figure l is a top view ot' my improved die, and Fig. 2 is a side view of the same. Fig. 3 is a side view of one ot' the chasers or cutters, and Fig. 4. is an end View ofthe same'. Fig. 5 is a top view of another form ot my invention, and Fig. 6 is a side view ofthe same.

A is an annular collet. B B B B are cutters or chasers, iittingin grooves upon the upper side of A sufficiently deep to admit of the upper side of the cutter being flush with the top oi' the collet A. These cutters and grooves may be ot' a taper or dovetailed sec tion, as well as rectangular, as shown in the drawing'. The inner end ot' the cutter B is furnished with the usual teeth orV cuttingedges, forming part of a screw-thread, as shown in Fig. 4. CC, 8vo., are adjusting-screws, for pressing the cutters inward when desired.

In Figs. 1 and 2 the head of the screw acts upon apshoulder, c, and in Figs. 5 and 6 the point of the screw acts directly upon the rear end of the chaser or cutter.

D D, dto., are clamp-screws for holding the cutters rmly in place when properly adjusted by means of the screws C. The head of the Screw D laps over the cutter, and rests in a notch, d, which is elongated in the direction of thev length of B,to allow of the requisite longitudinal motion.

In order to adjust the cutters, the screws D are loosened, and the screws C are turned so as to bring'the cuttingedges to the desired position. `The screws D are then clamped to hold them in place.

In place of the collet A, my improved cutters, with their adjusting and clamping screws, can be arranged, if desired, in a solid die-stock of any other required form-as, for instance, a square block, and this block may be provided, in the usual manner, with handle's forv turning. y

What I claim as my invention is- 1. A screw-cutting die consisting ofthe cutters B, moving longitudinally in grooves in the collet A, the adjusting-screws C, and the clam p-screws D, constructed and arranged substantially as herein described.w

2..The combination ot' the cutters B, arranged radially in a die-stock, and moving in suitable grooves, with adjusting-screws C and clamping-screws D, substantially as described.

JQHN J. GRANT.

Witnesses: i

'THEo. G. ELLIS,

WENDELL R. CURTIS. 

